The effects of inbreeding on the parental values of potato dihaploids

Dihaploids obtained from a somatically chromosome-doubled dihaploid potato were crossed with Solanum phureja clones. To test the effect of inbreeding, measurements were made of their seed production and the tuber yield, tuber number and mean tuber weight of their offspring. On average, seed production of the second generation dihaploids was higher than that of the original dihaploid progenitor. Progeny tuber yield and its components were little different from those of the original dihaploid's progeny. Tuber flesh quality, as measured lack of blemishes, was better in the offspring of second generation dihaploids.
It is suggested that the negative effects of producing second generation dihaploids are minor compared with producing the first generation dihaploid from a tetraploid, because most deleterious recessives have already been unmasked. The results indicated residual variation within the original dihaploid which could be exploited for plant breeding purposes.
An indicator of inbred status, alternative to the inbreeding coefficient, is suggested which could be applied to both diploids and tetraploids.     

Interspecific host discrimination and competition in Apoanagyrus (Epidinocarsis) lopezi and A.(E.)diversicornis, parasitoids of the cassava mealybug Phenacoccus manihoti

Abstract.

• 1 Choice experiments on interspecific host discrimination in A.lopezi and A. diversicornis were carried out on discs of cassava leaf containing four hosts (P.manihoti) that had been parasitized by the other species and four unparasitized hosts.
• 2 A.lopezi accepted both host types equally for oviposition, whereas A.diversicornis accepted fewer hosts that had been parasitized by A.lopezi than unparasitized ones. A.diversicornis is therefore capable of interspecific host discrimination, but such a capability was not demonstrated for A.lopezi.
• 3 Survival probability in singly parasitized hosts was 0.85 for both parasitoid species. When the time interval between ovipositions was 2 h or less, survival in multiparasitized hosts was 0.68 for A.lopezi and 0.17 for A.diversicornis, irrespective of priority. Increasing A.lopezi priority to 24±2h did not increase A.lopezi survival. A.diversicornis survival, however, increased to 0.43 when A.diversicornis was given 24 ± 2 h priority. A.diversicornis eggs took 19 h longer than A.lopezi eggs to hatch. This could explain the difference in competitive abilities in multiparasitized hosts.
• 4 The observed difference in host selection behaviour between A.lopezi and A.diversicornis is in accordance with the different benefits of multiparasitism: A.lopezi gains more than A.diversicornis because of its superior within-host competitive abilities.
• 5 Neither species avoided multiparasitism completely. The low survival probability of A.diversicornis in multiparasitized hosts may partly explain its failure to establish when introduced into Africa as part of a biological control programme of P.manihoti.

     

RESEARCH OF SELECTIVE TESTS FOR DISCERNING "AN EFFICIENT ASSESSOR" IN TEXTURE PROFILING

To find selective and predictive tests in texture profiling, a series of 20 tests and 2 texture profiles were submitted to 25 subjects. Selection was carried out according to ranking, scoring and a texture property knowledge questionnaire. Two profiles were then done on 5 Bolognese sauce and 8 rice samples. Assessors were assessed by Spearman correlation coefficients for ranking tests, F values for scoring, average square canonical correlation coefficients for measuring the dimensionality of individual sample space, product discrimination and response repeatability for both Bolognese sauce and rice samples.
Characterization test results showed that subject ability varied widely according to the test and the profile. Only one significant relationship between the texture property knowledge test and rice profile performances was found. More tests were successfully related to one or several texture attributes of both profiles. The ability to complete a complex profile could be discerned, albeit with difficulty, through simple selection tests.     

bel-2 protein in breast cancer cells obtained by fine needle aspiration (FNA): a preliminary report

The bcl-2 protein plays a role in the regulation of programmed cell death (PCD), overriding apoptosis. Its expression has been reported in breast ductal cells, where it is believed to be involved in the hormonal regulation of hyperplasia and involution. to date, bcl-2 gene product has not been investigated on breast cancer FNA. the expression of bcl-2 protein was evaluated using an immunoalkaline phosphatase technique in 54 pre-operative breast cancer aspirates and in paraffin-embedded sections from 20 matched surgical specimens. A high rate of bcl-2 protein expression was found on FNA samples (65%) and on the corresponding tissue sections (60%); there was a nearly absolute concordance in the two specimens, with 19/20 (95%) cases showing a concordant staining. These findings concur with the view that bcl-2 gene is frequently expressed in breast cancer, possibly through a hormonal-dependent pathway.     

Entamoeba histolytica: Collagenolytic Activity and Virulence1

Several axenic strains of pathogenic and nonpathogenic Entamoeba histolytica were tested for their capacity to digest native radioactive type I collagen gels and to produce liver abscesses when injected into the liver of newborn hamsters. The results demonstrate that the pathogenic strains of amebas (HM1:IMSS, HM3:IMSS, HM38:IMSS, and HK9) have a collagenolytic activity that closely correlates with their in vivo capacity to produce liver lesions. The nonpathogenic isolate (Laredo) did not show collagenolytic activity and failed to produce lesions in the liver of newborn hamsters. The results also demonstrate that type I collagen obtained from rodents and cats is degraded less by amebic collagenase than is bovine collagen, which is similar to human collagen. These findings suggest that species susceptibility to invasive infection may depend, among other factors, on the characteristics of the extracellular components of host tissues.     

Importance of Time Constants in an Open Flow System: Mathematical Correction of Fast Ethylene Kinetics in Physiological Studies

A mathematical analysis for fast changes of ethylene concentration in an open flow system (non-steady-state conditions) is presented and experimentally tested. In this way it becomes possible to determine true values of ethylene production in the minute range following physiological and environmental changes which influence ethylene evolution. By this procedure ethylene kinetics can also be compared in absolute values independent of flow rate and plant chamber volume.     

Glycolipid Degradation in Leaves of the Thermophilic Cucumis sativus as Affected by Light and Low-Temperature Treatment

Treatment of Cucumis leaf discs with light and low temperature (1°C) resulted in degradation of the total lipids. In addition, a decrease of the linolenic acid content of the glycolipids of leaves and leaf discs took place while at the same time an increase in the content of unidentified degradation products from the glycolipids was observed. The decrease of the linolenic acid content was not due to galactolipase activity, since no monogalactosyl diglyceride acyl hydrolase activity was found. Dark and low temperature did not alter the fatty acid composition. Blue light and low temperature resulted in a decrease of the linolenic acid content, while yellow-, red- and far red light in combination with low temperature were ineffective.